McpMux — Configure MCP servers once, connect every AI client

What is McpMux?

McpMux is a free and open-source (GPL-3.0) desktop app that runs a local MCP gateway. It eliminates the need to configure model context protocol (MCP) servers separately for every AI client (Cursor, Claude Desktop, VS Code, Windsurf, etc.) by centralizing server management into a single configurable gateway accessible at a single URL.

How to use McpMux?

Download McpMux for Windows, macOS, or Linux from mcpmux.com/download. Browse the built-in Discover tab to install servers, then paste the following JSON config into each AI client:

{
  "mcpServers": {
    "mcpmux": {
      "type": "http",
      "url": "http://localhost:45818/mcp"
    }
  }
}

That single config replaces all per-client configuration files.

Key features of McpMux

• Encrypted credentials stored in OS keychain (DPAPI/Keychain/libsecret)
• Built-in server registry for browsing and installing servers
• Isolated workspaces (Spaces) with their own servers and credentials
• Feature sets to switch active tools per task and avoid the 80-tool limit
• Per-client OAuth with one-click approval
• Automatic sync – changes propagate instantly to all connected clients

Use cases of McpMux

• A developer using multiple AI clients (Cursor, Claude, VS Code, Windsurf) who wants a single source of truth for MCP server configs
• A team sharing a set of MCP servers and credentials without duplicating plain-text config files
• Anyone needing to switch between project-specific tool sets (e.g., Android vs. webapp development) without exceeding tool limits
• A security-conscious user who wants API keys and credentials encrypted in the OS keychain rather than stored in plain-text JSON

FAQ from McpMux

What problem does McpMux solve?

Every AI client (Cursor, Claude Desktop, VS Code, Windsurf) requires its own configuration file for MCP servers, leading to duplicated configs and plain-text API keys. McpMux replaces all of them with one gateway that all clients connect to.

What are the runtime dependencies?

McpMux is built with Rust (Axum + SQLite + ring encryption) and React 19 + Tauri 2. It runs as a desktop app on Windows, macOS, and Linux and relies on the operating system’s native keychain for credential encryption.

Where are credentials and data stored?

Credentials are encrypted and stored in the OS keychain (DPAPI on Windows, Keychain on macOS, libsecret on Linux). Server configs and workspace data are stored locally in a SQLite database inside the app.

What transport and authentication does McpMux use?

The gateway listens on localhost:45818 using HTTP. Each AI client authenticates independently via per-client OAuth with one-click approval.

Are there any limits I should know about?

McpMux includes “Feature Sets” to switch active tools per task, which helps avoid the typical 80-tool limit imposed by many AI clients.